Worldwide sequence conservation of transmission-blocking vaccine candidate Pvs230 in Plasmodium vivax.

Pfs230, surface protein of gametocyte/gamete of the human malaria parasite, Plasmodium falciparum, is a prime candidate of malaria transmission-blocking vaccine. Plasmodium vivax has an ortholog of Pfs230 (Pvs230), however, there has been no study in any aspects on Pvs230 to date. To investigate whether Pvs230 can be a vivax malaria transmission-blocking vaccine, we performed evolutionary and population genetic analysis of the Pvs230 gene (pvs230: PVX_003905). Our analysis of Pvs230 and its orthologs in eight Plasmodium species revealed two distinctive parts: an interspecies variable part (IVP) containing species-specific oligopeptide repeats at the N-terminus and a 7.5kb interspecies conserved part (ICP) containing 14 cysteine-rich domains. Pvs230 was closely related to its orthologs, Pks230 and Pcys230, in monkey malaria parasites. Analysis of 113 pvs230 sequences obtained from worldwide, showed that nucleotide diversity is remarkably low in the non-repeat 8-kb region of pvs230 (θπ=0.00118) with 77 polymorphic nucleotide sites, 40 of which results in amino acid replacements. A signature of purifying selection but not of balancing selection was seen on pvs230. Functional and/or structural constraints may limit the level of polymorphism in pvs230. The observed limited polymorphism in pvs230 should ground for utilization of Pvs230 as an effective transmission-blocking vaccine.

[The effects of a novel local ventilation system to reduce the health hazard to students during gross anatomy courses].

Formaldehyde or formalin is indispensable not only as a preservative but also as a disinfectant of cadavers for gross anatomy. It has recently attracted a great deal of attention as a health hazard for students and lecturers. To reduce the concentration of formaldehyde gas (FAG), we improved a novel local ventilation system of the push-pull type. This is the first report dealing with the effects of this ventilation system on the health of students before (over 1 ppm) and after (0.1 ppm) the installation. The percentages of students with lacrymal symptoms or airway irritation were reduced to a third of what they were before the installation. In particular, the number of those with continuously strong symptoms was reduced to a sixth of the pre-installation levels. This local ventilation system draws in fresh air from outside, and directs it to the breathing zone of the students, effectively reducing their symptoms.

Comparison of inhibitory action of candesartan and enalapril on brain ischemia through inhibition of oxidative stress.

The effects of an angiotensin II type 1 (AT1) receptor blocker (ARB) on ischemic brain damage induced by middle cerebral artery (MCA) occlusion were compared with those of an angiotensin converting enzyme (ACE) inhibitor. Treatment of male C57BL/6J mice with an ARB, candesartan, reduced the brain ischemic area and neurological deficit after MCA occlusion at a non-hypotensive dose. In contrast, an ACE inhibitor, enalapril, did not reduce the brain ischemic area, and neurological deficit even at a hypotensive dose. Candesartan improved the reduction of brain surface blood flow after MCA occlusion, and inhibited the increase in superoxide production both in the cortex and brain arterial wall at non-hypotensive and hypotensive doses. However, enalapril did not affect the changes in blood flow and superoxide production in the brain after MCA occlusion. AT2 receptor expression in the ischemic area was increased at 3 h after MCA occlusion by pretreatment with candesartan, but not that with enalapril. AT1 receptor expression was neither affected by candesartan nor by enalapril. These results suggest that candesartan attenuated ischemic brain damage, at least partly, through inhibition of oxidative stress.